So, with one other person, we attempted a danger room on the first floor of Tier 3. It was a Jelly Room, but it had mostly those new shock jelly's... and it was practically impossible for us. Not only do they heal when they ignite themselves, they move so incredibly fast that its difficult to hit them. Plus, they can permanently stun lock you to death - happened to me twice, I got hit by one, got shocked, 4 others rushed in and I was permanently frozen due to the shock status, and all health gone in seconds. (Though honestly this occurs with every mob with shock status - wolvers do the same)
I know on their own or with just a couple, they aren't much of a threat: but in this danger room, we just couldn't get past it. Has anyone else dealt with this kind of danger room before? Did you get past it? The only way I can see is if we had a frost bomb of some sort. Swords don't seem to be an option, trying to close in on them just makes you too vulnerable to be permanently locked down. Alchemers bullets travel slow, so its difficult to hit them.
As far as I know, they're called Quicksilvers.
Anyhow, they're most dangerous in tight spaces.
They can also electricute each other at will.
They're WORSE than Oilers on fire.